Publication: Functional characterization of two members of histidine phosphatase superfamily in Mycobacterium tuberculosis
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2013
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eng
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Mahidol University
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BioMed Central
Bibliographic Citation
BMC Microbiology. Vol. 13, (2013), 292
Suggested Citation
Olabisi Oluwabukola Coker, Saradee Warit, Kamolchanok Rukseree, Pijug Summpunn, Therdsak Prammananan, Prasit Palittapongarnpim Functional characterization of two members of histidine phosphatase superfamily in Mycobacterium tuberculosis. BMC Microbiology. Vol. 13, (2013), 292. doi:10.1186/1471-2180-13-292 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/2731
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Title
Functional characterization of two members of histidine phosphatase superfamily in Mycobacterium tuberculosis
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Abstract
Background: Functional characterization of genes in important pathogenic bacteria such as Mycobacterium
tuberculosis is imperative. Rv2135c, which was originally annotated as conserved hypothetical, has been found to be
associated with membrane protein fractions of H37Rv strain. The gene appears to contain histidine phosphatase
motif common to both cofactor-dependent phosphoglycerate mutases and acid phosphatases in the histidine
phosphatase superfamily. The functions of many of the members of this superfamily are annotated based only on
similarity to known proteins using automatic annotation systems, which can be erroneous. In addition, the motif at
the N-terminal of Rv2135c is ‘RHA’ unlike ‘RHG’ found in most members of histidine phosphatase superfamily. These
necessitate the need for its experimental characterization. The crystal structure of Rv0489, another member of the
histidine phosphatase superfamily in M. tuberculosis, has been previously reported. However, its biochemical
characteristics remain unknown. In this study, Rv2135c and Rv0489 from M. tuberculosis were cloned and expressed
in Escherichia coli with 6 histidine residues tagged at the C terminal.
Results: Characterization of the purified recombinant proteins revealed that Rv0489 possesses phosphoglycerate
mutase activity while Rv2135c does not. However Rv2135c has an acid phosphatase activity with optimal pH of 5.8.
Kinetic parameters of Rv2135c and Rv0489 are studied, confirming that Rv0489 is a cofactor dependent
phosphoglycerate mutase of M. tuberculosis. Additional characterization showed that Rv2135c exists as a tetramer
while Rv0489 as a dimer in solution.
Conclusion: Most of the proteins orthologous to Rv2135c in other bacteria are annotated as phosphoglycerate
mutases or hypothetical proteins. It is possible that they are actually phosphatases. Experimental characterization of
a sufficiently large number of bacterial histidine phosphatases will increase the accuracy of the automatic
annotation systems towards a better understanding of this important group of enzymes.